1. 01 Jun, 2015 1 commit
    • Nicholas Bellinger's avatar
      target: Convert se_node_acl->device_list[] to RCU hlist · 29a05dee
      Nicholas Bellinger authored
      This patch converts se_node_acl->device_list[] table for mappedluns
      to modern RCU hlist_head usage in order to support an arbitrary number
      of node_acl lun mappings.
      
      It converts transport_lookup_*_lun() fast-path code to use RCU read path
      primitives when looking up se_dev_entry.  It adds a new hlist_head at
      se_node_acl->lun_entry_hlist for this purpose.
      
      For transport_lookup_cmd_lun() code, it works with existing per-cpu
      se_lun->lun_ref when associating se_cmd with se_lun + se_device.
      Also, go ahead and update core_create_device_list_for_node() +
      core_free_device_list_for_node() to use ->lun_entry_hlist.
      
      It also converts se_dev_entry->pr_ref_count access to use modern
      struct kref counting, and updates core_disable_device_list_for_node()
      to kref_put() and block on se_deve->pr_comp waiting for outstanding PR
      special-case PR references to drop, then invoke kfree_rcu() to wait
      for the RCU grace period to complete before releasing memory.
      
      So now that se_node_acl->lun_entry_hlist fast path access uses RCU
      protected pointers, go ahead and convert remaining non-fast path
      RCU updater code using ->lun_entry_lock to struct mutex to allow
      callers to block while walking se_node_acl->lun_entry_hlist.
      
      Finally drop the left-over core_clear_initiator_node_from_tpg() that
      originally cleared lun_access during se_node_acl shutdown, as post
      RCU conversion it now becomes duplicated logic.
      Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Sagi Grimberg <sagig@mellanox.com>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
      29a05dee
  2. 31 May, 2015 39 commits